Hot melt adhesives are widely used in the packaging industry to seal cardboard cases, trays and cartons.
Many types of packaging applications require the use of an adhesive that is both heat resistant and cold tolerant. The use of a hot melt adhesive with exceptionally high heat resistance and, in addition, good cold resistance is important in hot filled packaging applications, e.g., sealing and closing operations for cartons, cases or trays used for packaging molten cheese, yogurt or freshly baked goods, which are subsequently subjected to refrigeration or freezing. An adhesive having good heat resistance and good cold resistance is also needed to seal containers (cases, cartons, and the like) that are to be shipped by truck or railway. Sealed containers being transported and/or stored within a truck or rail car are exposed to very high temperatures in the summer (up to 165° F. or higher) and very low temperatures in the winter (down to about −20° F. or lower). Thus, hot melt adhesives used in packaging applications need to be strong enough such that the sealed containers will not pop open during the transportation process.
While hot melt adhesives based on ethylene vinyl acetate and/or ethylene n-butyl acrylate having been used in packaging applications, there continues to be a need for new and improved hot melts formulations, including formulations based on new polymers, that possess both high heat resistance and good cold adhesion. The current invention addresses this need.